Dry climates (B)
Also called: Group B climates · Topic: World Climate Classification: Koeppen's Scheme · NCERT: Class 11, Ch 11 "World Climate and Climate Change"
Meaning
Dry climates (B) form the Koeppen group in which potential evaporation (the water the air could take up) is greater than precipitation. It is the only group defined by moisture. All the others are defined by temperature. Group B covers the largest area of any group, roughly a quarter to a third of the land, between 15° and 60° in both hemispheres. It occurs in three settings: under the subtropical highs, where sinking air stops rain; on west coasts beside cold currents; and in mid-latitude interiors cut off from moist sea winds, often by mountains. It is split into BS (steppe, semi-arid) and BW (desert, arid).
Example
The Thar Desert of western Rajasthan (BWhw) is a dry climate under the subtropical high. Semi-arid parts of Rajasthan, Gujarat and Haryana are BShw.
Don't confuse with
- Cold climates (D, E): these are humid groups defined by low temperature. Some get little rain, but they are not classed as B.
Related concepts
- Subtropical steppe climate (BSh)
- Subtropical desert climate (BWh)
- Coastal desert
- Mid-latitude steppe climate (BSk)
- Mid-latitude desert climate (BWk)